DOE, NREL Release Reports on Cutting Energy Use in Half in Commercial Buildings

September 24, 2010

Reports detail strategies to save energy in large office buildings and large hospitals

The U.S. Department of Energy and its National Renewable Energy Laboratory (NREL) have released two technical reports that provide recommendations on how to achieve 50% energy savings in large office buildings and large hospitals. Conducted by NREL’s Commercial Buildings Group, under the direction of DOE’s Building Technologies Program, the studies support DOE’s goal of significantly improving the energy efficiency of new and existing commercial buildings across the United States.

Technical Support Document: Strategies for 50% Energy Savings in Large Office Buildings evaluates the potential for new large office buildings to achieve a 50% net onsite energy savings compared to a baseline standard (as defined by ANSI/ASHRAE/IESNA Standard 90.1-2004). The report found 50% energy savings can be achieved in both low-rise and high-rise office buildings in a broad range of U.S. climates. The analysis was conducted in 16 cities that represented different climate zones, such as hot and humid, hot and dry, marine, cold and humid, and cold and dry. The following energy-efficiency measures helped researchers reach the 50% energy-savings target:

Lighting power density was reduced in office spaces and occupancy sensors were used in infrequently occupied spaces.

High-efficiency boilers, chillers, air distribution units, and service water heating equipment were installed.

Plug loads were reduced by purchasing high-efficiency electronic equipment and using special controls that shut off equipment when not in use.

Large Hospital 50% Energy Savings: Technical Support Document details the technical analysis performed and the resulting design guidance that will enable large hospitals to achieve whole-building energy savings of at least 50% over the above standard. The large hospitals report also documents the modeling methods used to demonstrate how the design recommendations will help institutions meet or exceed the 50% energy-savings goal. This report found 50% energy savings can be achieved in large hospitals across all eight U.S. climate zones. Energy savings range from 50.6% to 61.3%, with the smallest savings in humid climates and extremely cold climates. The highest energy savings were achieved in marine climates, with relatively high energy savings achieved in dry climates. In general, for each climate type (humid, marine, and arid), savings were seen to decrease as the climate became progressively colder.

DOE commissions these types of technical reports, called technical support documents (TSDs), to describe the assumptions, methodologies, and analyses used to achieve certain levels of energy performance. In addition to the recently released TSDs, DOE has commissioned documents in the following categories of commercial buildings:

In many cases, technical support documents are the basis for Advanced Energy Design Guides (AEDGs), which are “how-to” guides that show architects, engineers, and building designers how to achieve above-code exemplary energy performance for buildings using existing technologies available today. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) works in collaboration with DOE, the American Institute of Architects, the Illuminating Engineering Society of North America, and the U.S. Green Building Council to develop and publish AEDGs.

In addition to the ASHRAE design guides, the results of these studies will be shared with DOE’s Commercial Building Energy Alliances. These alliances are public-private collaborations aimed at developing energy-efficient technologies and practices and sharing the information with commercial building owners and operators around the United States.

The mission of the Building Technologies Program (BTP) is to develop technologies, techniques, and tools for making buildings more energy efficient, productive, and affordable. BTP focuses on improving commercial and residential building components, energy modeling tools, building energy codes, and appliance standards. For more information, visit the Building Technologies Program Web site.